Comprehensive profiling and quantitation of oncogenic mutations in non small-cell lung carcinoma using single molecule amplification and re-sequencing technology

Gene-Guided Treatment Decision-Making in Non-Small Cell Lung Cancer - A Systematic Review

Decision-making in cancer treatment is part of clinicians’ everyday work, and it is especially challenging in non-small cell lung cancer (NSCLC) patients, for whom decisions are clearly dependent on gene alterations or the lack of them. The multimodality of treatments, involvement of gene alterations in defining systemic cancer therapies, and heterogeneous nature of tumors and their responsiveness provide extra challenges. This article reviews the existing literature to 2021 with extra effort to explore the role of genes and gene-driven therapies as part of decision-making. The process and elements in this decision-making participation are recognized and discussed comprehensively. Genetic health literacy aids are provided as a part of the review. Our systematic review, data extraction and analysis found that with current methods and broad gene panels, patients benefit from early molecular testing of liquid biopsy samples. An estimated 79% of liquid biopsy samples showed somatic mutations based on 8 original studies included in the systematic review. When both liquid biopsy samples and tissue samples are evaluated, the sensitivity to detect targetable mutations in NSCLC increases. We recommend early testing with liquid biopsy. Additional effort is needed for the logistics of obtaining and evaluating samples, and tissue samples should be saved and stored for tests that are not possible from liquid biopsy.

Tracking the evolution of untreated high-intermediate/high-risk diffuse large B-cell lymphoma by circulating tumour DNA

Diffuse large B-cell lymphoma (DLBCL) is a highly heterogenous malignancy, early identification of patients for relapse remains challenging. The potential to non-invasively monitor tumour evolutionary dynamics of DLBCL needs to be further established. In the present study, 17 tumour biopsy and 38 plasma samples from 38 patients with high-intermediate/high-risk DLBCL were evaluated at baseline. Longitudinal blood samples were also collected during therapy. Circulating tumour DNA (ctDNA) was analysed using targeted sequencing based on a gene panel via a recently developed methodology, circulating single-molecule amplification and re-sequencing technology (cSMART). We found that the most frequently mutated genes were tumour protein p53 (TP53; 42·1%), histone-lysine N-methyltransferase 2D (KMT2D; 28·9%), caspase recruitment domain family member 11 (CARD11; 21·1%), cAMP response element-binding protein binding protein (CREBBP; 15·8%), β₂ -microglobulin (B2M; 15·8%), and tumour necrosis factor alpha-induced protein 3 (TNFAIP3; 15·8%). The mutation profiles between ctDNA and matched tumour tissue showed good concordance; however, more mutation sites were detected in ctDNA samples. Either TP53 or B2M mutations before treatment predicted poor prognosis. Analysis of dynamic blood samples confirmed the utility of ctDNA for the real-time assessment of treatment response and revealed that the increases in ctDNA levels and changes in KMT2D mutation status could be useful predictors of disease progression. Our present results suggest that ctDNA is a promising method for the detection of mutation spectrum and serves as a biomarker for disease monitoring and predicting clinical recurrence.

Plasma EGFR mutation abundance affects clinical response to first-line EGFR-TKIs in patients with advanced non-small cell lung cancer

Background

Activated epidermal growth factor receptor (EGFR) mutation is the main pathogenic cause of non-small cell lung cancer (NSCLC) in Asia. However, the impact of plasma EGFR mutation abundance, especially of the ultra-low abundance of EGFR mutation detected by highly sensitive techniques on clinical outcomes of first-line EGFR tyrosine kinase inhibitors (TKIs) for advanced NSCLC patients remains unclear.

Methods

We qualitatively detected baseline EGFR status of NSCLC tissues using amplification-refractory mutation system and quantified the plasma abundance of EGFR mutations through next-generation sequencing (NGS). Every 8–12 weeks, we performed dynamic detection of plasma mutation abundance and imaging evaluation. We analyzed the association between plasma abundance of EGFR sensitizing mutations, tumor size, tumor shrinkage percentage, concomitant TP53 mutations, and clinical response to TKIs.

Results

This prospective study enrolled 135 patients with advanced NSCLC. The objective response rate (ORR) and disease control rate (DCR) for EGFR mutation–positive patients were 50.0% and 87.0%, respectively. When the cutoff value of plasma EGFR mutation abundance was 0.1%, the ORRs of TKI-treated patients were significantly different (60.0% for the >0.1% group vs. 21.4% for the ≤0.1% group, P=0.028). Median progression-free survival (PFS) was significantly longer for participants with a mutation abundance above 0.1% compared to those with a 0.01–0.1% abundance (log rank, P=0.0115). There was no significant association between plasma abundance of EGFR sensitizing mutations and tumor size, tumor shrinkage percentage, or concomitant TP53 mutations. Cox multivariate analysis demonstrated that plasma mutation abundance was an independent predictive factor for PFS [hazard ratio (HR) 2.41, 95% confidence interval (CI): 1.12–5.20; P=0.025]. We identified 11 participants with the acquired T790M resistance mutation according to serial dynamic plasma samples.

Conclusions

Liquid biopsy screening based on highly sensitive NGS is reliable for detecting drug resistance and actionable somatic mutations. The plasma abundance of the EGFR driver mutation affected clinical response to EGFR-TKIs in advanced NSCLC patients; prolongation of PFS was also observed in patients with an ultra-low abundance of EGFR sensitizing mutations.

Genetic profiling of primary and secondary tumors from patients with lung adenocarcinoma and bone metastases reveals targeted therapy options

Background

Patients newly diagnosed with lung adenocarcinoma with bone metastases (LABM) have poor survival rates after treatment with conventional therapies. To improve outcomes, we retrospectively investigated whether the application of a more comprehensive genetic test of tumor biopsies samples from LABM patients could provide the basis for treatment with more effective tyrosine kinase inhibitors (TKIs) regimens.

Methods

Fine needle biopsies were taken from the primary tumor (PT) and a secondary bone metastasis (BM) of 17 LABM patients before treatment. Simple genetic profiles for selecting therapies were initially obtained using an ARMS-PCR test for EGFR and ALK fusion mutations. More detailed genetic profiles of somatic exon SNVs and CNVs in 457 cancer-related genes were retrospectively derived using capture single molecule amplification and resequencing technology (capSMART).

Results

ARMS-PCR identified 14 EGFR positive, 3 EGFR negative and 1 ALK fusion positive patient. A therapy regimen incorporating TKIs Gefitinib and Crizotinib was offered to the EGFR and ALK fusion positive patients, respectively. With the exception of two patients, molecular profiling of matching PT and BM biopsies identified a highly shared somatic variant fingerprint, although the BMs exhibited additional genomic instability. In six of 13 EGFR positive patients and in all three EGFR negative patients, examination of the genetic profiles identified additional clinically significant mutations that are known or experimental drug targets for treatment of lung cancer.

Conclusion

Our findings firstly suggest that treatment regimens based on comprehensive genetic assessment of newly diagnosed LABM patients should target both the PT and secondary BMs, including rogue clones with potential to form new BMs. Second, the additional information gained should allow clinicians to design and implement more personalized treatment regimens and potentially improve outcomes for LABM patients.

Continual Improvement of the Reliability of EML4-ALK Rearrangement Detection in Non-Small-Cell Lung Cancer: A Long-Term Comparison of ALK Detection in China

The results of EML4-ALK testing are critical to manage ALK tyrosine kinase receptor inhibitor treatment. Thus, the accurate detection of ALK rearrangement is increasingly becoming a matter of serious concern. To address this issue, a long-term EML4-ALK proficiency testing (PT) scheme was launched in China in 2015, serving as an educational tool for assessing and improving the testing quality of EML4-ALK fusion detection. Responses across 20 different PT samples interrogating three different variants and wild-type samples were collected between 2015 and 2019. Performance was analyzed by evaluating the detection methods, kits, and pre-analytic practices used to further display the landscape of changing conditions of the reliability of EML4-ALK testing. During the 5 years, 3224 results reported from 988 laboratories were evaluated, with an overall error rate of 5.36%. Along with an increasing number of participating laboratories, the error rate within each of the different methods showed a significantly downward trend over the years. No obvious differences in the error rates were found regarding the testing methods or kit manufacturers. Moreover, the individual performance of the laboratories improved when they participated in more PT scheme rounds. The data demonstrated that the performance of individual Chinese laboratories for EML4-ALK testing continuously improved over time by participating PT schemes, regardless of their method. However, care must be taken in standardized operations and validations.

Cell-Free Circulating Tumour DNA Blood Testing to Detect EGFR T790M Mutation in People With Advanced Non-Small Cell Lung Cancer: A Health Technology Assessment

BACKGROUND

Cell-free circulating tumour DNA blood testing (also called liquid biopsy) can determine if a person with advanced non-small cell lung cancer (NSCLC) whose disease is progressing has developed the epidermal growth factor receptor (EGFR) T790M resistance mutation. Identifying this resistance mutation can help physicians choose appropriate treatment (i.e., osimertinib if positive and chemotherapy if negative). Tissue biopsy is typically used to look for the resistance mutation, but this is an invasive test that might not be feasible if the patient is too ill. We conducted a health technology assessment of liquid biopsy for people with advanced NSCLC, which included an evaluation of the diagnostic accuracy, clinical utility, safety, cost-effectiveness, and the budget impact of publicly funding liquid biopsy, as well as an evaluation of patient preferences and values.

METHODS

We performed a systematic literature search of the clinical evidence. We assessed the risk of bias of each included study using Risk of Bias in Systematic Reviews (ROBIS), Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2), Risk of Bias Among Non-randomized Studies (RoBANS), and the Cochrane risk of bias (ROB) tool and assessed quality of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. We performed a systematic economic literature search and conducted short-term and long-term cost-effectiveness and cost-utility analyses comparing liquid biopsy as a triage test, liquid biopsy alone, and tissue biopsy alone from a public payer perspective. We also analyzed the budget impact of publicly funding liquid biopsy for people in Ontario with advanced NSCLC. To assess the potential value of liquid biopsy, we spoke with people with lung cancer and people with an understanding of the process of liquid biopsy.

RESULTS

We included 19 studies (within a published systematic review) to examine diagnostic test accuracy and 12 studies to examine clinical utility. In patients with advanced NSCLC, liquid biopsy to detect the EGFR T790M resistance mutation demonstrated a positive and negative predictive value of 89% and 61%, respectively, a sensitivity of 68%, and specificity of 86%. No studies examined the clinical utility of liquid biopsy as a triage test. When NSCLC was treated appropriately, progression-free survival was similar in patients with and without the resistance mutation, as ascertained by liquid biopsy.We estimated that it costs about $700 to conduct a liquid biopsy and $2,500 to conduct a tissue biopsy. Our analyses showed that, when considering costs and effects directly related to testing, liquid biopsy (as a triage test, which means patients who test negative undergo a follow-up tissue biopsy, or alone, which means using only liquid biopsy) was less costly than tissue biopsy alone and led to fewer tissue biopsies. Using liquid biopsy as a triage test produced the most correct treatment decisions and greatest number of people who were given osimertinib.When considering long-term costs (i.e., treatment and care) and effects (i.e., life-years and quality-adjusted life-years [QALYs]), liquid biopsy as a triage test was the most effective and most costly strategy followed by liquid biopsy alone. Tissue biopsy alone was the least effective and least costly strategy. The incremental cost-effectiveness ratios (ICERs) of liquid biopsy as a triage test compared with liquid biopsy alone and of liquid biopsy alone compared with tissue biopsy alone were greater than $100,000 per QALY. However, this result was largely driven by the cost of osimertinib, which was used more often when liquid biopsy was used as a triage test.We estimated that the total annual budget impact of publicly funding liquid biopsy as a triage test in Ontario over the next 5 years would range from approximateily $60,000 in year 1 to $3 million in year 5.People with lung cancer with whom we spoke said that liquid biopsy would likely be an appropriate test for people with NSCLC given their frail condition and because it would avoid the pain and anxiety associated with tissue biopsy.

CONCLUSIONS

As a minimally invasive test, liquid biopsy identifies a high proportion of people with the EGFR T790M resistance mutation. This identification could better guide treatment for people with advanced NSCLC. However, its relatively low negative predictive value means it is best used as a triage test (i.e., followed by tissue biopsy if the liquid biopsy does not identify a resistance mutation). Liquid biopsy as a triage test is likely more effective than tissue biopsy alone. However, owing to the high cost of treatment, liquid biopsy may not be cost-effective. We estimated that publicly funding liquid biopsy as a triage test in Ontario would result in additional costs (related to more patients being treated) of between $0.06 million and $3 million over the next 5 years.

Comparison detection methods for EGFR in formalin-fixed paraffin-embedded tissues of patients with NSCLC

Epidermal growth factor receptor (EGFR) is an important gene in the development of lung cancer. Non-small cell lung cancer (NSCLC) is the most common lung cancer. In the present study, the expression of EGFR in 717 patients with NSCLC was detected by Ventana automatic immunohistochemical technique, and the samples was verified by Real-time PCR, and then the results were compared with the data acquired by next-generation sequencing technology (NGS), which is the high throughput, multiple sites for EGFR gene mutation testing. The expression of Ventana EGFR in 717 cases of NSCLC was detected by immunohistochemistry, and the positive rate was 60.70 % (435 / 717). The mutation rate of EGFR was 57.60 % (413/717). The coincidence rate of Ventana EGFR immunohistochemical assay and Real-time PCR assay reached 94.94 %, and the two had high consistency. The coincidence rate of Ventana EGFR immunohistochemical assay and NGS were high correlation. Based on these results, Ventana EGFR automatic immunohistochemical detection has high accuracy, simple operation process, low price and easy interpretation. It can be used as the preferred method for EGFR detection.

Comparison of the Amplification Refractory Mutation System, Super Amplification Refractory Mutation System, and Droplet Digital PCR for T790 M Mutation Detection in Non-small Cell Lung Cancer after Failure of Tyrosine Kinase Inhibitor Treatment

Plasma mutation detection has the advantages of non-invasiveness and accessibility. Here, we evaluated three methods, the amplification refractory mutation system (ARMS), second-generation ARMS (SuperARMS), and droplet digital PCR (ddPCR), to assess their concordance and feasibility for the detection of mutations in plasma samples. Non-small lung cancer patients with stage IIIB/IV that were resistant to epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment were enrolled. Blood samples were collected within 14 days after TKI resistance. Each sample was simultaneously assessed by the three methods. In total, 169 patients were enrolled; 54.4% were female, 72.2% were diagnosed with stage IV disease; and 97.6% had adenocarcinoma. T790 M mutations were detected in 42 (24.8%) of the 169 samples using ARMS, one of which carried the T790 M alone, 22 that also encoded exon 19 deletions, and 19 with L858R mutations. For the SuperARMS assay, 59 (34.9%) samples exhibited the T790 M mutation, and 110 (65.1%) showed no detectable T790 M mutation. ddPCR showed that 61 (36.1%) samples contained the T790 M mutation, whereas 108 (63.9%) were not positive. T790 M abundance ranged from 0.04% to 38.2%. The median T790 M abundance was 0.15% for total samples and 2.98% for T790 M mutation samples. The overall concordance was 78.7% (133/169) among ARMS, SuperARMS, and ddPCR. Compared with patients with stage III disease, patients with stage IV disease exhibited a higher T790 M mutation detection rate (28.7% vs. 14.9% by ARMS; 37.7% vs. 27.7% by SuperARMS; and 41.8% vs. 21.3% by ddPCR). Liquid biopsy showed promise and has the advantages of non-invasiveness and accessibility. T790 M detection based on circulating tumor DNA showed high concordance. Compared with non-digital platforms, ddPCR showed higher sensitivity and provided both frequency and abundance information, which might be important for treatment decisions.

[Detection and Clinical Significance of Abundance of EGFR Mutation]

Non-small cell lung cancer (NSCLC) patients, with sensitive epidermal growth factor receptor (EGFR) mutations react well to tyrosine kinase inhibitors (TKIs). However, the efficacy of TKIs on patients with the same mutant types differs dramatically. It is implied that the different quantities of mutant alleles could be one of the reasons underlying. Patients with high abundance of EGFR mutation might benefit more from TKIs. There are no universal standards for the definition of EGFR mutant abundance. Abundance could be semi-quantified according to the different sensitivities of detection methods, quantified with quantifying detection techniques such as digital PCR or next generation sequencing, or quantified based on the expression of mutant proteins. The different abundances of primary and metastatic diseases could reflect the heterogeneity of the tumors. The pre-treatment level or the dynamic change of EGFR mutant abundance could help observe the course of the diseases and predict the efficacy of TKIs. TKIs resistance could be detected by change of abundance prior to image manifestations. Besides, the abundance of T790M could also predict drug efficacy and resistance of the first and third generation TKIs. Thus the detection of EGFR mutant abundance has important clinical significance. The standardization and correction of abundance needs more exploration.

CRISPR/Cas9 Technology-Based Xenograft Tumors as Candidate Reference Materials for Multiple EML4-ALK Rearrangements Testing

The echinoderm microtubule-associated protein-like 4 and anaplastic lymphoma kinase (ALK) receptor tyrosine kinase (EML4-ALK) rearrangement is an important biomarker that plays a pivotal role in therapeutic decision making for non-small-cell lung cancer (NSCLC) patients. Ensuring accuracy and reproducibility of EML4-ALK testing by fluorescence in situ hybridization, immunohistochemistry, RT-PCR, and next-generation sequencing requires reliable reference materials for monitoring assay sensitivity and specificity. Herein, we developed novel reference materials for various kinds of EML4-ALK testing. CRISPR/Cas9 was used to edit various NSCLC cell lines containing EML4-ALK rearrangement variants 1, 2, and 3a/b. After s.c. inoculation, the formalin-fixed, paraffin-embedded (FFPE) samples from xenografts were prepared and tested for suitability as candidate reference materials by fluorescence in situ hybridization, immunohistochemistry, RT-PCR, and next-generation sequencing. Sample validation and commutability assessments showed that all types of FFPE samples derived from xenograft tumors have typical histological structures, and EML4-ALK testing results were similar to the clinical ALK-positive NSCLC specimens. Among the four methods for EML4-ALK detection, the validation test showed 100% concordance. Furthermore, these novel FFPE reference materials showed good stability and homogeneity. Without limitations on variant types and production, our novel FFPE samples based on CRISPR/Cas9 editing and xenografts are suitable as candidate reference materials for the validation, verification, internal quality control, and proficiency testing of EML4-ALK detection.

Application of Single-Molecule Amplification and Resequencing Technology for Broad Surveillance of Plasma Mutations in Patients with Advanced Lung Adenocarcinoma

Liquid biopsy to access the circulating tumor DNA is a promising surrogate for invasive tumor genotyping. We designed a multiplex assay based on circulating single-molecule amplification and resequencing technology (cSMART) to simultaneously detect and quantitate hot spot EGFR, KRAS, BRAF, ERBB2, and ALK plasma DNA variants in 103 patients with advanced lung adenocarcinoma. In validation studies using an analytical mutation standard, the sensitivity of the assay for EGFR mutation detection was at least 0.1% and specificity was 100%. The diagnostic detection sensitivity was one mutant molecule per 2 mL of plasma. The most frequently detected plasma mutations were EGFR variants L858R (21.4%), exon 19 deletions (19.4%), T790M (9.7%), and KRAS G12X variants (9.7%). Rarer were BRAF V600X (1.95%) and ERBB2 exon 20 (0.97%) variants. In single samples, four novel EGFR exon 19 deletions, one KIF5B-ALK, and two EML4-ALK variants were also detected. From comparisons of 103 matched plasma and tumor specimen genotypes, 75 (72.8%) were concordant, 9 (8.8%) were partially concordant, and 19 (18.4%) were discordant. Overall, the combined positive and negative concordance rate for detection of each oncogenic variant exceeded 90%. On the basis of these findings, we propose that cSMART displays the diagnostic hallmarks of a comprehensive plasma genotyping assay, with potential application for precisely monitoring changes in plasma mutation levels in response to targeted drug therapy.